1. Field of the Invention
The present invention relates to a bias circuit for driving an avalanche photodiode with high multiplication factor.
2. Related Background Art
An avalanche photodiode (APD) is a semiconductor photodetector which has high photodetection sensitivity and high speed of response utilizing the avalanche multiplication. The APD is used to perform the photodetection with high sensitivity. However, each APD has an operating characteristic which varies according to temperature during operation. As a temperature compensating circuit for the APD, circuits disclosed in "Japanese Patent Laid-open No. Shou 60-111540 (111540/1985)", "Japanese Patent Laid-open No. Shou 60-180347 (180347/1985)", and "Japanese Patent Laid-open No. Hei 2-44218 (44218/1990)" have been known.